Estimated protective effectiveness of intramuscular immune serum globulin post-exposure prophylaxis during a measles outbreak in British Columbia, Canada, 2014

The estimated crude IM ISG PEP protective effectiveness against measles disease within 8-21 days post-ISG administration was 69%. Accuracy of this estimated protective effectiveness is vulnerable to assumptions and uncertainties in ascertaining exposure details and pre-exposure immune status. Increasing the Canadian recommended measles IM ISG PEP dose from 0.25 to 0.5 ml/kg (up to 15 ml maximum volume) may increase protective effectiveness.